Data from several cancer screening studies are being analyzed to gain a better understanding of the impact and consequences of such screening in various population settings. The results can be used by NCI in establishing cancer control policy. These databases also provide the opportunity for the testing and development of new techniques for data analysis. Results from the Health Insurance Plan of New York (HIP) breast cancer screening trial continue to indicate a long-term reduction in breast cancer mortality. In collaboration with the Field Studies and Statistics Program of the Division of Cancer Cause and Prevention (FSS), long-term case survival patterns and co-variables are being related to population mortality measures to determine when and in which subsets of cases the screening benefit occurred. Patterns of cause of death among breast cancer cases are being studied to distinguish between postponement of death and cure. A group collaborating through the International Agency for Research on Cancer (IARC) is analyzing the cervical cancer screening programs in Scandinavia and Aberdeen, Scotland. The objective is to estimate false negative rates and natural history characteristics and relate these to the varying screening frequencies and delivery mechanisms in the participating countries. Two occupational high risk groups are under scrutiny. With FSS people, the bladder cancer screening program at the DuPont Company is being analyzed to relate disease characteristics and outcome to cytology and blood tests, smoking history and exposure to benzidine and B-naphthylamine. With FSS and the National Institute of Occupational Safety and Health (NIOSH), updated followup data are being collected in a study of sputum cytology screening for lung cancer among uranium miners. The relationships among cytology classification, radiation exposure, smoking history, lung cancer, and mortality data will be analyzed. Participation has begun in an International Union Against Cancer (UICC) screening evaluation project which will review screening data from worldwide sources and develop guidelines for UICC members.